Re: BUG #4919: CREATE USER command slows down system performance

Alvaro Herrera <alvherre@commandprompt.com> writes:
> toruvinn wrote:
>> I was always wondering, though, why PostgreSQL uses this approach and not
>> its catalogs.

> It does use the catalog for most things.  THe flatfile is used for the
> situations where the catalogs are not yet ready to be read.

Now that we have SQL-level CONNECT privilege, I wonder just how much
functionality would be lost if we got rid of the flat files and told
people they had to use CONNECT to do any per-user or per-database
access control.

The main point I can see offhand is that password checking would have
to be done a lot later in the startup sequence, with correspondingly
more cycles wasted to reject bad passwords.

            regards, tom lane